<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/jquery.js"></script>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
       .box{
        width: 360px;
        border: 1px solid blue;
        display: flex;
        flex-wrap: wrap;
        margin: 20px 50px;
       }
       .w{
        width: 100px;
        height: 100px;
        text-align: center;
        line-height: 100px;
        font-size: 30px;
        font-weight: 700;
        color: black;
        margin: 10px;
       }
       .one{
        background-color: aqua;
       }
       .two{
        background-color: rgb(212, 45, 176);
       }
       .three{
        background-color: rgb(90, 81, 218);
       }
       .four{
        background-color: rgb(37, 219, 46);
       }
       .five{
        background-color: rgb(146, 136, 47);
       }
       .six{
        background-color: rgb(74, 173, 212);
       }
    </style>
</head>
<body>
    <div class="box">
      <div class="one w">1</div>
      <div class="two w">2</div>
      <div class="three w">3</div>
      <div class="four w">4</div>
      <div class="five w">5</div>
      <div class="six w">6</div>
    </div>
    <script>
      $(function() {
        $(".box div").hover(function() {
            $(this).stop().fadeTo(400,1);
        },function() {
            $(this).stop().fadeTo(400,.2)
        })
      })
    //    $(this).siblings().fadeTo(400,.2)
    </script>
</body>
</html>